1. Field of the Invention
The invention relates to hybrid electronic and photoelectric devices manufactured by means of thin film and monolithic layering techniques.
2. Description of Prior Art
Most electronic devices are now made using thin layers of material on a supporting substrate such as silicon, gallium arsenide, mercury cadmium telluride, sapphire, plastic or one of various other similar types of materials. These devices are being combined with one another and other film structures in layers to form more exotic devices. Upon interfacing these layers and/or devices with each other special considerations have to be addressed such as electrical isolation, electrical conduction, thermal isolation, differential thermal expansion, and chemical compatibility.
As an example, large arrays of infrared photodetectors made with HgCdTe or pyroelectric materials are being combined with Charge-Coupled Devices (CCD's) made on silicon substrates. The photodiodes are very temperature sensitive and become extremely noisy unless maintained near the boiling point of liquid nitrogen. The CCD's work well at room temperatures and become an undesirable thermal load on the photodiodes unless adequate insulation is placed between them.
In applicant's patent application Ser. No. 07/823,749, filed Jan. 22, 1992 and issued Apr. 5, 1994 as U.S. Pat. No. 5,300,807, there is described a method of forming a thin layer of plastic which is sandwiched between hybrid devices, such as detector arrays and CCD's, during their assembly. It has been proposed that parts of these hybrid structures not be preassembled, but that the arrays be formed on the CCD structures, preferably on an aerogel insulating layer. It would also be advantageous not to preform the cross-linking electrodes on the CCD's; so that the same CCD's can be utilized in a variety of Time Delay Integration (TDI) readout scenarios with the same or different arrays. The surface of the aerogel, however, is too porous to form the semiconductor or metallization layers on, and the plastic preparation layer previously suggested cannot withstand the rigors of sputtering and other techniques used to form these layers.